Remote controlling apparatus



May 17, 1938. c. s. SNAVELY REMOTE CONTROLLING APPARATUS Filed July 17, 1929 NNNQQN 4 Sheets-Sheet l QEMQ INVENTOR Z May 17, 1938. SNAVELY 2,117,580

REMOTE CONTROLLING APPARATUS Filed July 17, 1929 4 SheetsSheet 2 NPQ [a r? N N V ass/ n y ZZZQQ'R'M May 17, 1938. c. s. SNAVELY REMOTE CONTROLLING APPARATUS Filed July 17, 1929 4 Sheets-Sheet 4 Patented May 17, 1938 REMOTE CONTROLLING APPARATUS Clarence s. Snavely, Pittsburgh, Pa... assignor to The Union Switch & Signal Company, Swissvale, Pa., a corporation of Pennsylvania Application July 17, 1929, Serial No. 378,894

74 Claims.

My invention relates to remote controlling apparatus, and particularly to apparatus adapted to be used in a centralized traffic controlling system for railroads for controlling a plurality of train governing devices, such as railway switches or signals, from a central point, such for example, as a train dispatchers oflice, and for also indicating at said ofilce the condition of such devices and traffic conditions adjacent such devices, such as the presence of trains adjacent the devices.

It is customary in systems of the type described to deliver control codes to a line circuit extending between the dispatchers omce and the remote point at which the governing devices are located for effecting the control of these devices, and for delivering indication codes to this line circuit from the remote point for informing the operator at the dispatchers oflice concerning the condition of the devices and also concerning traffic conditions adjacent such devices. The codes usually employed for these purposes are made up of code elements having different lengths, or different numbers of impulses, and the receiving apparatus is selectively responsive to the lengths of these codeelements or to the number of impulses in each code element. I propose to utilize code elements having different characters, not requiring time measurement or counting devices to distinguish between them, and I also propose 30 to provide separate devices selectively responsive to each such code element. With this arrangement, the receiving apparatus is arranged to respond selectively to the sequence of operation of these devices and the system is therefore in- 35 dependent of the lengths of time required for the separate code elements.

The apparatus of my invention is an improvement upon that disclosed in my copending application, Serial No. 362,948, filed May 14, 1929, for Remote controlling apparatus, and also upon that disclosed in an application by Lloyd V. Lewis, Serial No. 291,465, filed July 9, 1928, for Remote controlling apparatus.

I will describe one form of remote controlling apparatus embodying my invention, and will then point out the novel features thereof in claims.

In the accompanying drawings, Figs. 1 and 2, when placed end to end with Fig. 1 on the left form a diagrammatic view illustrating one form of remote controlling apparatus embodying my invention, Fig. 1 showing the equipment located at the control oflice and Fig. 2 showing the equiplment located at a field station. Fig. 3 is a sec- 55 ti'onal view showing. one form of decoding relay suitable for use in the apparatus illustrated in Figs-1 and 2. Figs. 4, 5 and 6 are sectional views along the lines IV-IV, V-V and VI-VI, respectively, of Fig. 3. Fig. 7 is a detail view of a portion of the decoding relay shown in Fig. 3 as 1;; WOlld appear if viewedalong the arrow VH1 in Similar reference characters refer to similar parts in each of the several views.

Referring first to Fig. l, I have shown the equipment at the ofllce for transmitting codes made up of code elements of different characters. In the particular embodiment here shown, each code eiementis an impulse of periodic current of a distinctive frequency and these currents are supplied by three alternators X, Y and Z which are driven by a motor m comprising an armature 5 and a field 6. The armature 5 is constantly connected across the terminals B and C of a source of energy not shown in the drawings. The field 6 is connected with terminals B and C through a resistance 1 which is at times shunted by a contact 8 of a centrifugal governor h operated by motor 1n. With this arrangement, it will be apparent that the motor m operates at a constant speed, and since the alternators X, Y and Z are operatively connected with this motor, it follows that the frequencies of the currents delivered by these alternators are substantially constant.

Means are provided for selectively connecting the alternators X, Y and Z with a pair of line wires 3 and i which extend from the oflice to each of the remote stations at which there are located devices which it is desired to control from the oifice. The connections of the alternators to these line wires are controlled by three delivery, magnets each designated by the reference character AD with an exponent corresponding to the associated alternator. For example, when delivery magnet AD is energized, the front contact 9 of this magnet is closed and alternator x is then connected across line wires I and 3. In similar manner, the energization of magnet .AD connects alternator Y across line wires l and 3, and the energization of magnet AD connects alternator Z across line wires l and 3.

The delivery magnets AD AD? and AD are controlled in part by' a distributor comprising a stepping contactor l? operated by a magnet F. This stepping contactor is similar in all respects to the stepping contactor which is described and claimed in my copending application for Letters Patent, Serial No. 362,948, hereinbefore referred to. This stepping contactor comprises a spider 38 operated by a pawl 24 driven by magnet F. The spider co-operates with a plurality of fixd contact segments, designated by the reference characters 35 to 40, and arranged in such manner that an arm of the spider engages one of these segments at all times. As shown in the drawings, the spider engages. segment 35. If, now, the magnet F is energized, pawl 34 is'moved along one step on the spider 85, and when the magnet F is next de-energized, the spider 33 is advanced one step so that an arm of the spider then engages contact 38. In similar manner, successive energizations and deenergizations of the stepping magnet F advance the spider 38 from each segment of the stepping contactor to the next segment in order.

Associated with the stepping contactor P is a master relay J, a starting relay :2: and two timing relays 1'' and a, the functions of which will be described hereinafter.

The control omce is provided with a plurality of panels, one for each remote station which is to be controlled from the office, and each panel is provided with manually oscillatable switching devices for separately controlling governing devices at the associated station. Referring particularly to panel B on Fig. 1, this panel is provided with two switching devices BE and BE, each comprise ing a lever l2 in the form of a cam which operates a cam follower l3. The lever I 2 also controls a movable contact l4 which may be moved into engagement with a selected one of a plurality of fixed contacts. The switching devices BE and BE are employed as the control levers for the track switch and for the signals at station B of Fig. 2, and'as herein illustrated, are mounted upon a panel board or track model having a miniature representation of the track layout on the face thereof. The portion of the track diagram allocated to panel B includes a miniature movable switch point in a location corresponding to that of the track switch at station B, and provided with a handle 21 by which it may be moved in a plane parallel to the panel to a normal or reverse position to indicate the route to be taken by a train in passing over the switch. Handle 21 is operatively connected to the lever l2 of switching device BE as indicated by a dotted line connection on the drawings, so that when the miniature switch point is moved to normal or reverse to visually indicate the position to be assumed by the track switch lever [2 of device BE is moved to a corresponding position. The signal control lever has a handle 28 on the face of the panel, which is provided with a pointer for indicating the direction of train movement established over the track switch, and also with a connection, as indicated by a dotted line on the drawings, for operating the lever l2 of switching device BE. The portion of the track model which is allocated to panel B is also provided with a plurality of indication lamps 29, 30, 3| and 32, which are controlled as will be described hereinafter for informing the operator of the condition of the apparatus under the control of the handles 21 and 28. o For purposes of simplicity, panel B is the only one which is illustrated complete in the drawings portions only of two. other panels designated C and D being, illustrated in Fig. 1.

Referring now'to panel B, .the switching devices BE and BE control a starting contact comprising a movable member l8 which is pivoted at point I 8 and which is arranged to move to the left when thelever of either switching device is operated. Whenthe member i 8 is urged to the left, contact arm 20 is moved out of engagement with contact 22, which it normally engages, and is swung into engagement with contact 2!. This movement of arm 20 permits a latch 23'to drop under the influence of gravity to a position in which the return of the arm 20 is prevented.

Each panel is also provided with a code determining or code sending relay, designated by the reference character W with a prefix corresponding to the location, and having a winding 25 which controls a finger 24 and a plurality of contacts. When winding 25 of relay BW is energized, the finger 24 is swung to the left, and the tip of this finger then engages'the arm 20, and at the same time lifts the latch 23. Under these conditions, therefore, the arm 20 is unlatched, but is held in its left-hand position, so that contact 20-2| is closed, until winding 25 is de-energized.

The switching device BE as already .pointed out, is employed to operate the track switch at the corresponding remote station and when the handle 21 occupies the position shown in the drawings, contact |4I6 operated by lever I2 is closed. If the handle 21 is operated to its reverse position, however, contact i4-l5 becomes closed. The handle 28 which operates switching device BE is utilized to govern the railway signals at the same station and when this handle occupies the position illustrated in the drawings, contact l4l5 of switching device BE is closed. If handle 28 is swung to the left, contact i4il is closed and if handle 28 is swung to the right, contact I4-l5 is closed.

The line wires i and 3 extend to all of the remote stations which are controlled from the ofllce in Fig. 1, line wire 3 serving as a common return and line wire I including in series a transformer at each way station. Referring particularly to Fig. 2, it will be seen that the primary of transformer t is included in series with line wire I at station B and similar transformers are located at each-of the other stations.

Governing devices of any suitable type may be controlled by apparatus embodying my invention, but for the purposes of explanation I have illustrated at station B, a section of power operated railway track a-b provided with a railway switch 50 leading into a siding 5|. The section a-b is provided with a track circuit including a battery 52 connected across the rails adjacent one end of the section and a track relay v connected across the rails adjacent the other end of the section. The switch 50 is controlled by a motor 9 comprising an armature 53 and a field 54, which motor is controlled in part by two switch relays p and p Switch 50,

in turn, controls a pole changer 55 which governs the polarity of current supplied from terminals B and C to an indication relay k, as will be apparent from the drawings. Relay k is energized in the normal direction, so that. its polar contacts are swung to the left, when switch 50 occupies its normal position. When the switch 50 occupies its reverse position, however, relay k is energized in the reverse direction, so that its polar contacts are swung to the right. When switch 50 occupies any intermediate position, indication relay k is de-energized sothat its front contacts are open. Switch 50 also controls two contacts 56 and 51. Contact 55 is closed at all timesexcept when the switch occupies its full reverse position, and contact 51 is closed at all times except when the switch occupies its full normal position.

Eastbound traflic through the section 0-?) is controlled by two signals 10 and to which, as here shown, are mounted upon the same mast. In similar manner, westbound traffic is governed by two signals 10 and w. The signals w, w, w and w are controlled in part by two signa relays q and q. l

The switch relays p and p and the signal relays q and q at station B are controlled by receiving apparatus which will be described in detail hereinafter.

As shown in the drawings, the switching devices Bill and BE on panel B at the control office occupy their normal positions and switch 80 at station B occupies its normal position. Switch relays p and p are both deenergized, and the signal relays q and q are also deenergized so that all signals at station B occupy their stop positions. In explaining the operation of the apparatus as a whole, I will first assume that the operator wishes to reverse switch 50 at station B. In order to accomplish this result he moves the handle 2! of switching device 3E to the reverse position indicated by the dotted lines in the drawings. As a result, the cam follower l3 operated by switching, device BE is moved to the left, thereby swinging member l8 to the left and closing contact 20--2l. At the same time, contact I9 is opened. Latch 23 now engages the arm 28 and holds this arm in engagement with contact 2|. When the handle 21 has reached its full reverse position, member l8 returns to the position in which it is shown in the drawings, thereby closing contact l9, but contact 28-2l remains closed. A circuit is now completed from terminal B, over back contact 42 of relay at, contact 43-43 of master relay J resistance 44, contact 20-2l of panel B, contact l9 operated by member l8 of panel B, and winding 25 of relay 3' to terminal C. Relay 13 therefore becomes energized, and moves finger 24 to the left. This operation releases latch 23, but closes contact 28-24 and holds the arm 28 in engagement with contact 2|. It should also be noted that this operation of finger 24 closes the group of code setting contacts located to the right of the finger in the drawings. When contact 20-24 closes, current flows from terminal B, over back contact 42 of relay a, winding 58 of relay .1, contact 24-2ll of panel B, contact 20-2l of panel B, contact l9 and winding 25 of relay B to terminal C. The potential drop across resistance 44 insures a sufficient electromotlve force to energize winding 58 over the type, and it is to be understood that each of these relays is adapted to be operated by a momentary impulse of current and to maintain its contact closed in the last-operated position when de-' energized.

The closing of contact 43--43 of relay J energizes stepping magnet F of stepping contactor P over a circuit which passes from terminal B, over back contact 42 of relay 9:, contact 43--43 of relay J winding of magnet F and back contact 45 of relay 5* to terminal C. This energization of magnet 1" does not move the spider 33 of the stepping contactor, but front contact 48 of the magnet is closed so'that terminal B is connected with the spider 33 which is now in engagement with the fixed segment 35. Each segment oi the stepping contactor is connected with a selected one of the delivery magnets AD AD or AD depending upon the connections which are controlled by the contacts actuated by the relay B of panel B. For convenience, the segments of the contactor are brought out to bus bars and the delivery magnets are also connected with bus bars, cross connections between these two sets qf bus bars being controlled, in part directly by the contacts of the code sending relays, and in part by the position of the switching devices ateach panel.

The first four code elements of each control code codes originating at the same panel, the remaining two elements of the code being utilized for operating a particular function at the selected station, and being dependent upon the position of the switching device of the particular panel.

For purposes of explanation, I will assume that the first element of the code necessary for selecting station B consists of an impulse of current of the frequency supplied by alternator Y, and that the bus for connections are made accordingly. When stepping magnet F becomes energized, a circuit is completed from terminal 3. over front contact 48 of magnet F contact 3335 of stepping contactor P contact 48 of code setting relay B and winding of delivery magnet AD to terminal C. The delivery magnet AD therefore becomes energized, and the closing of contact ill of this magnet connects alternator Y across line wires I and 3, and delivers an impulse of current from alternator Y to the line wires to form the first code element. When the stepping magnet F became energized, front contact 46 closed, and current was supplied from terminal B, over front contact 46 of magnet F and winding of relay i to terminal C. Relay i therefore becomes energized. Relay is then connected directly with the terminals B and C, over front contact 41 of relay i When relay :i becomes energized, the opening of back contact 45 of this relay interrupts the circuit previously traced for the stepping magnet F When magnet F releases, it opens front contacts 46 and 48, and advances the spider 33 one step into engagement with segment 36. The opening of front contact 48 of magnet F interrupts the circuit for the delivery magnet AD and terminates the first element of the code. Furthermore, the opening of front contact 48 of this magnet de-energizes relay i and this relay in turn releases relay 7". When back contact 45 of relay 9' closes, a circuit is again completed for the stepping magnet F and when this magnet becomes energized, energy is supplied to the delivery magnet which is connected with seg ment 36, (in this case delivery magnet AD so that the second element of the code is made up of an impulse of current of the frequency supplied by alternator X. The energization of magnet F also sets the relays i and 1' into operation as described hereinbefore, to de-energize the magnet F terminating the second impulse of the code and advancing spider 33 of the stepping contactor P into engagement with segment 31. The operation just described is repeated for the third and fourth elements of the code, the circuits being apparent from the drawings without tracing them in detail. It should be noted, however, that as here shown the third element of the code is supplied by alternator Z, and the fourth element of the code is supplied by alternator Y. After the delivery of the fourth element of the code, the spider 33 is in engagement with segment 39 and when the magnet F next becomes energized, the fifth element of the code is supplied to line wires I and 3 in accordance with the position of the switching device Bill which as previously described, controls the track switch at station B. Since lever 21 has been reversed, contact lll5 of this switching device is closed, so that the fifth impulse of the code is supplied by alternator Y. In similar manner, the sixth impulse of the code is controlled by the position of the switching device BE, which now occupies its normal position, so that its contact H-l6 is closed and the sixth element of the code is therefore also supplied by alternator Y.

The de-energization of magnet F6 following the sixth element of the code advances the spider 33 into engagement with segment 4| and when magnet F next becomes energized, current flows from terminal B, over front contact 48 of magnet F contact 334l of stepping contactor P and winding of relay :1: to terminal C. Relay .2: therefore becomes energized and interrupts, at back contact 42 thereon, the holding circuit for relay BW of panel B. This relay therefore becomes de-energized and releases the finger 24. Since this finger now holds latch 23 out of engagement with the arm 20, the release of relay BW allows arm 20 to return to its original position to close contact 2022. Furthermore, the closing of front contact of relay :1: energizes the winding 59 of relay J thereby energizing this-relay in its normal position and closing contact 43-43 The opening of the contact 4343 of the master relay J interrupts the circuit for stepping magnet F and advances the spider 33 into engagement with segment 35. Relay a: is therefore de-energized, and relays i and j are de-energized so that all portions of the apparatus are restored to the positions in which they are shown in the drawings, and the equipment is again ready to initiate the transmission of a control code to the line circuit.

During the operations just described, it will be apparent that line wires i and 3 have been supplied with a code made up of six code elements, each element being an impulse of current of a selected frequency, the sequence of these frequencies being determined in part by the panel from which the code originated and in part by the positions of the switching device at thatpanel.

Referring now to Fig. 2, it will be clear that any code originating at the control oflice, and supplied to line wires l and 3, traverses the primary of transformers t at station B. The secondary of this transformer therefore has induced in it, impulses of current, the frequencies of which correspond to the frequencies of the code elements supplied to line Wires and 3.

Each station is provided with a plurality of devices which are selectively responsive to the different characters of code elements supplied to the line wires. For example, these devices may be ordinary relays included in circuits which are tuned respectively to resonance at the frequency of the several code elements. As shown in Fig.

2, the secondary of transformer t supplies energy to three relays BG BG and BG The circuit including relay 36- is tuned to resonance, as by a reactor and a condenser ll, so as to provide a communication channel which is selectively responsive to current of the frequency supplied by alternator X. Relay 3G will therefore close its front contact only in response to a code element supplied from alternator X at the dispatchers ofllce. In similar manner, relays BG and BG are tuned to resonance at the frequencies of the currents supplied by alternators Y and Z, respectively, so that relay BG closes its front contact only in response to a code element supplied by alternator Y, and relay IBG closes its front contact only in response to a code element supplied from alternator Z. The reference character BH designates a relay which is also supplied with energy from the secondary of transformer t and is arranged to be energized when any code element is being supplied to the line wires i and 3. Relay BH is somewhat slowacting, so that this relay becomes energized at the beginning of any control code and remains energized until the conclusion of the code.

In response to the control code previously described, therefore, relay BH at station B is energized at all times during the reception of this code, and selected ones of relays BG BG and BG are energized successively in a definite sequence depending upon the sequence of the several current impulses of different frequencies forming the control code.

It is desirable to control the apparatus at the remote station in accordance with the sequence of operation of the relays G at that station. For this purpose, I provide at each station, a plurality of decoding relays-which are controlled by the associated relays G to respond selectively to specific control codes. These decoding relays are designated by the reference characters N with prefixes corresponding to the location, and with suitable distinguishing exponents. Decoding relays operating in the manner described may be constructed in a number of ways, and I have illustrated only one form of decoding relay and wish it to be particularly understood that I do not limit myself to this particular embodiment.

Referring now to Figs. 3 to '7, inclusive, I have illustrated in detail one form of decoding relay N suitable for use in apparatus embodying my rality of stepping magnets and a holding magnet. The holding magnet is designated by the reference character 62 and ,one of the stepping magnets is provided for each of the associated relays G and each is designated by the reference character 62 with an exponent corresponding to the frequency of the code element during which the stepping magnet is energized. As here shown, the holding magnet and the stepping magnets are arranged side by side on a magnetizable core 63 which is provided with outstanding legs II, as best seen in Fig. 6, certain of such legs thus forming parts of the magnetic circuits for adjacent stepping magnets. The decoding relay N also comprises a rotatable shaft 66 supported in suitable journals, and biased, by means of a spring 61, to the position in which it is shown in the drawings, and in which position acontact arm 68 on the shaft engages a fixed stop 69. Rigidly attached to the shaft 66 are a plurality of driving disks each designated by the reference character 64 with a suitable distinguishing exponent. Each of these disks is provided with a plurality of openings 86 (see Fig. 6) which may be provided with magnetizable slugs I6. Pivotally supported on trunnions 14 between each two magnetizabie legs II is a stepping yoke comprising a T-shaped element 13 (see Fig. 7) of nori magnetic material to the opposite sides of which are attached two spaced magnetizable fingers 15 which are disposed on opposite sides of the associated driving disk 64. As best shown in Fig. 6, each element 13 with its associated fingers I is biased, by means of a spring 11, against an ad-' justable stop '18. When the parts occupy these positions, the fingers 15 are adjacent to, but out of alignment with, enlarged pole pieces I2 attached to the extremities of the adjacent legs ll. As shown in Fig. 6, a slug l6 occupies the opening 86 which is between the fingers 15. If, now, the stepping magnet 62 becomes energized, the element i3 with the associated fingers I5 is rotated in a clockwise direction by the tendency of the fingers 15 to move into alignment with the pole pieces 12. During this movement, the flux from the magnet 62 also passes between fingers 15 through the slug 16, so that when the fingers move, as described above, the driving disk SP is also moved. Each of the stepping magnets controls a driving disk in the manner just described. The holding magnet 62, illustrated in Figs. 4 and 5, is provided with two upstanding magnetizable legs 'I9 terminating on opposite sides of the holding disk 64 which is provided with a plurality of slugs 16 similar to those described in connection with the driving disks. The holding disk is provided with slugs corresponding to every stepping position of the shaft 66, whereas, slugs are inserted in the driving disks only in those openings 86 corresponding to the positions in which it is desired that an energization of the associated magnet should advance the shaft 66. As illustrated in Fig. 6, for example, the disk 64 has only two slugs 16 so positioned that this particular disk can advance shaft 66 only if winding 62 becomes energized during the first or the fourth element of a code. To facilitate adjustment of the slugs 16, the openings 86 may be partially covered by a retaining plate 65 (see Figs.5 and 6), and provided with a slot 9! which may be brought opposite any opening to permit the withdrawal or insertion of a slug. The parts are so proportioned that if the driving magnets are energized in a predetermined sequence corresponding to a definite control code, the last code element will rotate the shaft 66 to a position in which the arm 68 engages a fixed contact 16.

As indicated in Fig. 3, each stepping magnet is connected with terminals B and C over front contact I52 of the corresponding holding relay H and a front contact of the corresponding stepping relay. The holding magnet, however, is energized over a front contact of the holding relay and back contacts of all of the stepping relays in series.

The decoding relay illustrated in the drawings is designed for operatlon upon codes having six elements. For example, if it were desired to adjust the relay shown in Fig. 3 to respond to the control code supplied as described hereinbefore to the line wires I and 3 for reversing the switch at station B, slugs 16 would be placed in openings 86 in the driving disk GA corresponding to the first, fourth, fifth and sixth steps in the rotation of shaft 66. Furthermore, a slug would be placed in the opening 66 of driving disk 64 corresponding to the third driving position and a slug would be placed in the opening 86 of disk 64* corresponding to the second driving position. 'With the parts constructed in this manner, the first code element received energizes relays H and G Fig. 3. Since driving disk 64 has a slug in the first position, the operation of the stepping magnet 62 in response to operation of relay G advances the shaft 66 one step. At the conclusion of the first code element, relay G becomes deenergized but relay H remains closed due to its slow releasing characteristics, so that the holding magnet 62 is energized, thereby holding the shaft 66 in the position to which it has been moved, and bringing the second opening 86 of each driving disk into position to be operated upon by the corresponding fingers 15. During the second code element, relay G becomes energized and since the driving disk 64 has a slug in the second position, the energization of stepping magnet 62 advances the shaft 66 another step. The operation of the decoding relay N during subsequent code elements, will be readily understood from the foregoing, it being necessary here to state only that a decoding relay N cannot be operated to close its contact-68-|6 unless its stepping magnets are energized in a definite predetermined sequence.

It should also be pointed out that if a decoding relay has been partially operated, so that its shaft 66 is rotated away from its initial position, and a code element is received which energizes a stepping magnet for which there is no slug in the driving disk, the opening of the circuit for the holding magnet during this code element allows the shaft 66 to return to its initial position, thereby eifectively preventing the operation of the contacts 68-46 in response to any code except the particular one for which the decoding relay is designed to operate.

Returning now to a consideration of Fig. 2, the decoding relays N at station B are constructed to respond selectively to the control codes originating at panel B of the dispatchers ofifice. For example, in response to the control code delivered when handle 21 on panel B is moved to its reverse position, the decoding relay BN at station B closes its contact 66-46 for a brief interval of time. During this interval, current flows at station B,

from terminal B through winding 8i of relay 3L contact 68'l6 of decoding relay BN and winding 62 of relay BL to terminal C. Relay B1? was already energized in its reverse position so that this relay suffers no change as a result of the operation of relay BN Relay BL now becomes energized in its reverse direction, however; and when this happens, the closing of contact 86-43 of relay BI. completes a circuit from terminal B, over contact 83-83, contact 56 operated by switch 56 and winding of switch relay p to terminal C. Relay 1) therefore becomes energized and motor 9 is then actuated by current which flows from terminal B, over front contact 64 of track relay 2), front contact 85 of switch relay p armature 53 of motor g, front contact 86 of relay p and field 54 of motor 9, to terminal C. When this circuit is closed, motor g operates to drive switch 56 toward its reverse position. When the switch has attained its full reverse position, contact 56 opens, thereby interrupting the circuit for relay p and allowing this relay to release and de-energize the motor g.

If the operator wishes to restore the switch at station E to its normal position, he may do so by" restoring the handle 21 on panel B to its normal position. .When this happens, the operation of the cam l2 actuates the transmitting apparatus at the ofilce in the same manner as previously explained and a control code is then delivered to line wires I and 3 which is identical to that previously described except that the fifth element of this code is now made up of an impulse of current supplied by alternator X, since contact l4l6 operated by handle 21 is now closed and as a result the delivery magnet AD is connected with the segment 39 of the stepping contactor P to produce the fifth element of the code. When this code is received at station E, the decoding relay BN is the only relay which closes its contact 68-10. When this happens, current flows from terminal B, through winding 87 of relay BL contact 68--l0 of decoding relay BN and winding 82 of relay BL to terminal C. Relay BL remains in its reverse position, but relay BL is now restored to its normal position, whereupon current flows fromterminal B, through normal contact 83-83 of relay BL contact 51 operated by switch 50, and winding of switch relay 9 to terminal C. When relay p becomes energized an operating circuit is closed for motor 9 from terminal B, over front contact 88 of track relay 1:, front contact 89 of relay p armature 53 of motor 9, front contact 98 of relay p and field 5'4 of motor 9 to terminal C. Motor g is then actuated to drive switch 50 toward its normal position and when the switch attains its full normal position, contact 51 opens. thereby de-energizing relay p and stopping the motor 9.

In similar manner, the signals at station B are selectively controlled by the remaining decoding relays at this station. For example, if the operator wishes to clear the eastbound signal at station B, he operates handle 28 to its right-hand position, thereby delivering to the line wires 1 and 3 a control code which actuates the relays BG BG and BG at station B in a sequence which energizes decoding relay BN at station B. When this relay closes its contact, current flows from terminal B, through winding 81 of relay BL contact 68-10 of relay BN winding 92 of relay EU, and winding 93 of relay BL to terminal C. Relays BL and BL therefore remain in the normal position, and relay 3L also becomes energized in the normal direction. When this happens, current flows from terminal B, through contact 94-44 of relay BL, contact 95-95 of relay BL and winding of relay q to terminal C. Relay q therefore becomes energized and since switch 58 now occupies its normal position so that indication relay k is energized in the normal direction, this operation of relay q clears the signal w The operating circuit for this signal may be traced from terminal B, over front contact 96 of relay '0, front contact 91 of relay q frontcontact 98 of relay it, normal contact 99 of relay is, and operating mechanism of signal to to terminal C.

I will next assume that switch 50 at station B occupies its reverse position and that the operator moves handle 28 to its right-hand position to clear the eastbound signal. The control code, then delivered from panel B, actuates decoding relay BN When this happens, current flows from terminal B, through winding 8| of relay 3L contact 68'|0 of relay BN winding 92 of relay BL winding 93 of relay BL to terminal C. As a'result, relays BL and BL are both energized in the normal direction and relay BL is energized in the reverse direction. Current then flows from terminal B over normal contacts of relays BL and BU to energize relay (1 as described hereinbefore. Since the switch now occupies its reverse positiomhowever, the indication relay is is energized in its reverse direction and the signal operating circuit now completed is from terminal B, over front contact 96 of relay v, front contact 91 of relay q front contact 98 of relay k, reverse contact 99 of relay is and operating mechanism of signal 10 to terminal C.

In similar manner, the operation of the handle 4 28 on panel B to clear a Westbound signal actuates decoding relay BN or BN at station B according as-the switch is normal or reverse, respectively at station B, and the operation of either of relays BN or BN results in the energization of relay q, the circuits being similar to those provided for the control of relay q Furthermore, when relay q is energized an operating circuit is closed for signal 20 or for signal 10 according as the indication relay k is'energized in its reverse or normal direction.

It should be noted that each control code originating at the ofilce conveys information concerning the positions of both the switch lever and the signal lever on the-corresponding panel. Moreover, this information is translated at the remote station so that the apparatus at the remote station coincides at all times with the positions of the apparatus on the panel at the control oifice. One advantage of this arrangement is that only one control code is necessary to change from any condition of apparatus at the remote station to any other condition and a consequent saving is effected in the total length of time during which the line circuit is in use.

In order to inform the operator concerning the condition of the devices at each' remote station, I provide each panel with indicating devices, here shown as electric lamps which are controlled in accordance with thepositions of the devices at the remote station. For accomplishing the control of these indication devices, I utilize indication codes similar to the control codes previously described and transmitted from the field stations to the control oflice. These codes consist of code elements of different frequencies and in order to obviate the necessity of a plurality of alternators similar to X, Y and Z at each remote station, I utilize an additional line wire 2 extending from the ofiice to each remote station. The alternators X, Y and Z are all constantly connected across the line wires 2 and 3 at the ofiice, one of the relays AG AG or AG being included in series with each alternator and tuned to resonance at the frequency of the current supplied by the corresponding alternator. For example, relay AG is included in the series with alternator X across line wires 2 and 3 and is tuned to resonance by some suitable means, such as a reactor I53 and a condenser I54.

For the purpose of operating the relays AG AG and AG selectively, from any remote station, I provide each such remote station with a plurality of delivery magnets, each of which is arranged when energized to connect across line wires 2 and 3 at the remote station a shunt path which is tuned to resonance at the frequency of the current delivered by a particular one of the alternators at the dispatchers oiilce.

Referring particularly to Fig. 2, it will be seen that the delivery magnets BD BD and BD at station B are each effective when energized to connect across wires 2 and 3 a. tuned path designated by the reference character d with a distinguishing exponent and each including a condenser I2I and a reactor I22. The tuned paths d are separately tuned to resonance at the frequencies of the current supplied by altemators X,

Y and Z and it follows when delivery magnet BD at station Y is energized, relay A6? at the office becomes energized. Similarly, the energization of delivery magnet BD at station B picks up relay AG at the oflice and the energization of relay 13D at station B picks up relay AG at the oiflce. The delivery magnets at station B are energized in definite sequences by means of a stepping contactor P similar to the stepping contactor at the oflice except that in the present embodiment the stepping contactor P has an additional segment 9 so that indication codes are made up of seven code elements instead of six code elements as is the case with control codes.

This additional code element isintroduced into i the indication codes for the purpose of conveying certain information to the office which could not be conveyed with an indication code of six code elements.

' and 1'' are controlled in accordance with the posioffice.

tion of switch 50 at station B. Indication relays .1 and r are associated with the indication of the positions of the signals at station B. Indication relays r and r are controlled in part by the track relay 1: at station B and are utilized to inform the operator when a train, having occupied section a-b, leaves this section.

Since indication codes can originate at any one of a number of stations, it is manifest that some provision must be made for preventing interference between indication codes originating at different stations. For this purpose, I have provided checking and locking apparatusat each remote station which utilizes the common wire 3 and an additional wire 4 which extends between remote stations. Since this wire 4 is used for only checking and locking between remote stations, it is not necessary to continue this wire to the control trated in the drawings is similar to the checking and locking system described and claimed in my -co-pending application Serial No. 362,948, re-

ferred to hereinbefore. For this purpose station B is provided with a sectionalizing relay S a line relay R a motor relay M a delay relay K and an additional relay T and each of the other remote stations is provided with similar apparatus. Each sectionalizingrelay S is normally de-energized and under these conditions, each line relay is connected in series with line wire 4 over a back contact I05 of the associated sectionalizing relay and a battery I04 so that the line relays are all normally energized. Relay T is normally de-energized and relays M and K are also normally de-energized.

when the master relay J becomes energized in the reverse direction, the checking and locking apparatus at station B is set into operation. At the conclusion of this checking and locking operation, if relay F becomes energized, the transmitting equipment is actuated to deliver a code to the line wires 2 and 3.

The checking and locking system illus-' I will now'd'escribe in detail" the operation of the checking and locking. apparatus. when .relay J becomes energized in the reverse direction, the sectionalizing relay S picks up, the circuit for this relay passing from terminal B, over front contact I'of r'elay R back contact III of delay relay KB, winding of relay S and reverse contact I 02I02 of master relay J to terminal C. It should be pointed out that relay S can become energized only if the line is clear; that is, if no other remote station is delivering a code to the line circuit, because'under these conditions, as will be described hereinafter, the normally closed line circuit including line wires 3 and 4 is open and relay R is de-energized so that the circuit just traced is open. Furthermore, the closing of relay S insures that the line has been cleared for a definite interval of time because when relay R becomes de-energized, relay K is energized and this relay is slow releasing and holds its back contact open to prevent closing of the circuit for relay S for a brief interval of time after, relay R again becomes energized. When relay S becomes energized, thus insuring that the line circuit is clear and has been clear for a definite time interval, the opening of back contact I05 of relay S disconnects line wire 4 to all stations more remote from the offlce than station B. At the same time, however, a local circuit is completed for relay R over front contact I05 of relay S and back contact I00 of relay lay S to terminal 0. When relay T picks up it interrupts, at back contact I09, the circuit for relay R so that the latter relay releases. When relay R closes its back contact I00, the operating circuit for relay K is closed and this relay picks up. The closing'of relay K interrupts the circuits for relays '1 and S and completes a snubbing or holding circuit for these two relays in series which may be traced from terminal C over front contact I03 of relay S winding of relay T winding of relay S and reverse contact I02---I02 of relay J back to terminal C. Due to this snubbing circuit, relay 8 holds its front contacts closed, but relay T is quick-acting and closes its back contact I09. When this happens, relay 1'12. picks up provided theline is clear, and a circuit is then closed for the motor relay M from terminal B, over front contact I00 of relay R front contact IOI of relay K (now, de-energized but holding due to its slow-releasing characteristics), winding of relay M and front contact I06 of relay 8* to terminal C. Relay M therefore becomes energized and completes a stick circuit for relay S from terminal B, over front contact I08 of relay M winding of relay S and reverse contacts I02--I02 of relay J to terminal C. Relay S therefore remains in its energized condition. Furthermore, a stick circuit is now closed for relay M including its own front contact I 01 and front contact I06 of relay S The closing of the motor relay M also picks up relay 'I' over front contact I00 of relay M and front contact I03 of relay T so that relay T opens its back contact I09 and deenergizes relay R Relay R therefore opens and holds relay K energized, and the apparatus remains in'this condition during the transmission of a code. It will be noted that relay M does not become energized unless relay R is energized, thereby indicating that the line is clear in advance, and unless relay S is energized, thereby indicating that the'line in the rear of station B is locked out. When motor relay M is energized a circuit is completed for stepping magnet I" of stepping. contactor P from terminal B, over front contact III of relay M winding of stepping magnet F back contact II2 of relay 7' and reverse magnet I(I2-III2 of master relay J to terminal C. The transmitting apparatus is then set into operation to deliver an indication code to the line wires 2 and 3.

In explaining the operation of the indication apparatus, I will assume that all parts of the apparatus occupy the positions in which they are shown in the drawings and that switch 50 at station B is moved to its reverse position. When this operation of the switch commences, relay is becomes de-energized and current then flows from terminal B, over back contact II3 of relay k, thence through winding I of relay 1' and winding II5 of relay r in parallel to terminal C. Relay 1- is thus operated to its reverse position and relay 1'' is operated to its normal position. When the switch 58 attains its full reverse position, relay is becomes energized in the reverse direction and relay J is then reversed by the closing of a starting circuit which may be traced from terminal B, over front contact H3 of relay it, reverse contact II6I Iii of relay r winding II? of relay 1 and winding H8 of relay J to terminal C. The closing of this circuit restores relay r to its reverse position and operates relay-J to its reverse position. This operation of relay J initiates the checking and locking operation previously described, and if the line 4 is clear, as will be the case if no other remote station is transmitting an indication code, relay F becomes energized. When this happens, current flows from terminal B, over front contact I20 of magnet F contact 33-35 of stepping contactor P and winding of delivery magnet BD to terminal C. The delivery magnet BD therefore becomes energized to connect the tuned path 11 across line wires 2 and 3, thereby picking up relay AG at the ofilce. Another result of the closing of magnet F is to energize relay i The closing of front contact I33 of relay 1' picks up relay :i thereby opening, at back contact I I2, the circuit for magnet F which releases and advances the stepping contactor P to the next position. The operation continues in a manner similar to that described in connection with the apparatus at the oflice, each position of the stepping contactor' producing a distinctive code element, the sequence of these elements being determined by the connections of the delivery magnets with the segments of the stepping contactor. The first four elements of the code are the same for all indication codes originating at the same station, and are utilized for selecting the corresponding panel at the office. The fifth element of the code, however, is controlled by relay T6 in accordance with the condition of the track section a-b. ,As shown in the drawings, relay r occupies its normal position with contacts I23 I23 closed so that when contact 33-39 of stepping contractor P is closed, the delivery magnet BD is energized to pick up relay AG at the oifice for' the fifth element of the code. Similarly, the sixth element of the code is controlled in accordance with the positions of the signals at station B, and since these signals are all at stop, relay 1' as hereinafter explained will have been reversed, closing contacts l24---I24 to cause segment I. of the stepping contactor to be connected with delivery magnet BD so that the sixth v element of the code picks up relay AG at the office. The seventh element of the indication code is controlled in accordance with the position of the switch and in the present instance, segment H9 is connected, over reverse contact l25-I25 of relay 1'", front contact I26 of relay k, and reverse contact I21 01' relay k, with delivery magnet BD During the seventh element of the code, therefore, magnet BD becomes energized to pick up relay AG at the oflice. It should be noted that when delivery magnet BD is energized during this last element of the code, winding I23 of relay r is also energized thereby restoring relay r to its normal position. The relay r therefore serves to store the indication initiated by the movement of the relay k in response to a reversal of the switch, by maintaining the starting circuit for rel'ay J closed until the corresponding in-' dication has actually been delivered to the omce. At the conclusion of the seventh element of the code, the contact 334I of contactor P is closed, and when magnet F next becomes energized, current is supplied to winding 1330i relay J thereby restoring this relay to its normal position. When this happens, the stepping magnet F is energized, thereby advancing the spider 33 one step to close contact 3335 and places the apparatus in condition to start the delivery of another indication code. Furthermore, the opening of contact IlJI-IIJZ of master relay J opens the stick circuit for relay S, which thereupon releases and de-energizes relays M and T The de-energ'ization of relay S restores the normal line circuit, and if the line is clear, relay R becomes energized and drops relay K to restore the apparatus to its normal condition.

Referring now to Fig. 1, is will be observed that the relays AG AG and AG control a relay A which is energized when any one of the three relays just mentioned, is energized. The control office is also provided with a'plurality of decoding relays AN AN, etc., each of which is similar to the decoding relays located at the remote stations, except that the decoding relays at the ofllce, being designed for operation upon indication codes having seven elements per code, each have seven positions in each of the driving disks for magnetic slugs I6. For purposes of economy I prefer to use for each item of information received from the remote stations the same final elements of the indication codes originating at all stations. For example, the indication switch reverse" will be made up of seven code elements the first four of which will be distinctive for each station, the last three of which will be the same for all stations. By this means I can utilize a single decoding relay responsive to all indication codes which terminate in the three code elements corresponding to a switch reverse code and by employing a separate decoding relay for each panel, I can distinguish at which station the indication code originates. As shown in Fig. 1 a decoding relay B is arranged to operate in response to any indication code originating at station B, and when contact Bit-III of this relay closes, an auxiliary relay f becomes energized. Since relay B is adjusted to respond to any indication code originating from station E, this relay becomes energized in response to the indication code just described. This indication code also actuates decoding relay AN Since relay ,f is now energized, the closing of contact 68-40 of relay AN completes a circuit from terminal B, through winding I35 of relay AIF, winding I36 of relay AL frontcontact I31 of relay 1. and contact 88-10 of relay AN to terminal C. The closing of this circuit has no effect upon relay AL", but relay AL becomes energized in the reverse di-' rection and current then flows from terminal B,

over normal contact NIB-I38 of relay AL, re-

verse contact I 39-439 of relay AL, and lamp 30 to terminal 0. Lamp 30 is therefore lighted, and since lamp 29 was extinguished by the reversal of relay AL the lighting of lamp 30 gives the operator a positive indication that the switch at station B now occupies its reverse position.

If now the switch 50 at station B is restored to its normal position, relay It becomes de-energized at the beginning of this movement, thereby energizing winding II4 of relay 1' and winding II5 of relay 1' and causing relay 1' to be operated to reverse and relay 1' to be operated to normal.

When the switch has attained its full normal position, the consequent energization of relay is completes a circuit from terminal B, over front contact II3 of relay is, reverse contact II6--I I6 of relay 1' winding II! of relay 1', and winding N8 of relay J to terminal C. Relays r and J are then operated to reverse and this operation of the master relay J initiates the checking and locking operation described hereinbefore. At the conclusion of this operation the stepping magnet F becomes energized and the apparatus then proceeds to deliver to the oifice an indication code in the manner described hereinbefore, with the exception that the seventh element of this code is produced by operation of delivery magnet BD the circuit for the delivery magnet under these conditions passing from terminal B, over front contact I20 of stepping magnet F contact 33-I I9 of contactor P contact I25---I25 of relay T2, front contact I25 of relay it, normal contact I2'I of relay 7c, and winding of delivery magnet 13D to terminal C. It will be noted that the circuit just traced is provided with a branch which passes from reverse contact I25l25 of relay r through winding I28 of relay 1' to terminal C. The relay 1 is therefore restored to normal, opening the starting circuit so that relay J will be restored to normal at the conclusion of the indication code.

The indication code thus supplied to the office operates relays AG AG and AG in a definite sequence which results in the actuation of decoding relays B and AN These relays do not operate until the last element of the code is received and when this happens, relay f becomes energized and a circuit is then completed from terminal B, through winding I35 of relay ALF, winding M0 of relay AL front contact I4I of relay f, and contact 68--'I0 of relay AN to terminal C. Relays AL and AL are thus both energized in the normal directions, thereby extinguishing lamp 30 on panel B and completing a circuit for lamp 29 from, terminal B, over normal contact I38---I38 of relay AL normal contact I39---I39 of relay AL and lamp 29 to terminal C. The lighting of lamp 29 therefore informs the operator that the switch at station B occupies its normal position.

As will be explained below, an indication code can be initiated at station B by other means than by the operation of switch '50, as for example, when a signal relay q becomes energized or released, or when the track relay 2) becomes energized. Each indication code, however, conveys complete information to the office concerning the condition of all of the apparatus at the station where the code originated. If an indication code is delivered from station B when switch 50 is unlocked, that is, when the switch does not occupy either extreme position, the indication relay It will be de-energized, operating relay r .to reverse, and operating relay 1' to normal to close contact I25 to the left. Under these conditions, the seventh element of the code will be obtained by energizing the delivery magnet BD The indication code thus delivered to the office energizes relays B and AN, whereupon a circuit is completed from terminal B, through winding I42 of relay AL, front contact I43 of relay j and contact 69-10 of relay AN to terminal C. Relay ALF is then energized in the reverse direction and the circuits for both lamps 29 and 30 are broken at normal contact "0-438 of relay AL. Under these conditions, both lamps 29 and 30 remain extinguished, thereby informing the operator that the switch at station B is unlocked.

I will now assume that signal relay q is energized to clear an eastbound signal. The energization of this relay completes a circuit from terminal B, over backcontact I44 of relay q, front contact I29 of relay q, winding I30 of relay r normal contact I3II3I of relay 1' and winding III! of relay J to terminal C. The consequent reversal of relay J initiates the delivery of an indication code from station B, and relay 1' is at the same time operated to normal to close contact I24 to the left, so that the sixth element of the code is produced by energizing relay BD over a circuit which extends from terminal B, contact I20 of relay F stepping contacts 3340, left-hand contact I24 of relay 1', asymmetric unit I55, relay BD to terminal C. Relay r is energized in the reverse direction over a branch of this circuit which extends from the upper terminal of asymmetric unit I55 through winding I32 of relay 1' to terminal C. Asymmetric unit I55 serves to prevent the flow of current in the reverse direction in the branch of this circuit leading to relay BD and it follows therefore that ,the normal direction to close contact I45-I45= Lamp 3I is then extinguished and lamp 32 is lighted, thereby informing the operator that a signal is cleared at station B. The same indication would have been received had relay q been energized at station B so that the indication does not inform the operator which signal is clear. By observing the position of handle 20, however, he can determine the direction of traffic which has been set up at the station and by observing which of the lamps 29 or 30 is lighted, he can determine the position of the switch and hence the particular one of the signals which is clear. It should be noted that in the indication code just described, the seventh element of the code is controlled in accordance with the position of the switch, and the decoding relays at the oilice are I44 of relay q, back contact I29 of relay q the reverse winding of relay 1', reverse contact I3I--I8I of relay 1' and winding N8 of relay J to terminal 0. The consequent reversal of relays J and r initiates the delivery of an indication code in which the sixth element is produced by energization of delivery magnet BD over a circuit including stepping contacts 33-40 similar to that already traced but which includes reverse contacts I24-I24 of relay r Relay 7' is energized in the normal direction over a. branch of this circuit to again close contacts I BI-flti a and to open the starting circuit. When this code is received at the dispatcher's omce, it energizes relays AN and B. In addition one oi the relays AM, AN 'or AN is actuated, depending upon the position of the switch at the station. When relays AN and 2B are energized, relay AL is energized in the reverse direction by a circuit which will be obvious from the drawings, and lamp 82 is then extinguished and lamp Si is lighted to indicate to the operator that all signals at station B are at stop. It will be noted that during the delivery of the sixth element of the indication code from station B, one winding or the other of relay 7' is in each case energized in parallel with the delivery magnet and is energized by current supplied over contacts 3340 so that this relay is put into a position to open the starting circuit for the indication code which is delivered.

The track relay 2) controls relays r and r in a manner similar to the control of relays r and r by relay 70 except that there is, of course, no polarized contact on relay 2; entering into this control. It will be obvious, without tracing the operation in detail, that when relay 1' is normal, the fifth element of codes originating from station B, is produced by energizing delivery. magnet BD If relay 1) is de-energized, however, relay 1 becomes reversed, and then when relay 1) again becomes energized, as upon the departure of a train from section ab, relays r and J are operated to reverse and a code is delivered from station B which has its fifth element pro duced by energization of magnet BD by the closing of a circuit which includes stepping contacts 3339 and contacts Iii-423 of relay 1'. Relay 1 is energized in the normal direction over a branch circuit when the stepping contacts 3339 become closed, while relay 1 is restored to normal at the end of the code when stepping contacts 33-4I become closed. This indication code energizes relays AN and B at the ofiice. It is customary in usual practice to indicate the passage of trains through the portion of track controlled by apparatus embodying my invention on a graphic recorder, rather than by lamps on the control panel. I therefore provide a graphic recorder having a magnet I46 controlling a pen I 41 which operates upon a moving record sheet I48. When relays B and AN are energized, the magnet I46 on the graphic recorder is energized over front contact I49 of relay f, and contact Bil-10 of relay AN to record upon sheet I48 the departure of the train from section ab.

It will therefore be apparent that with apparatus embodying my invention, the operator at the dispatchers ofllce has before him at all times complete information of the condition of all apparatus at each remote station. This information is all conveyed by means of codes which are distinguished, not by the lengths of code elements, and not by the number of impulses in different code elements, but by the sequence in which code elements of different characters are delivered to a line circuit. One advantage of this feature is'that all code elements may be of equal lengths and the length of a code element may be very short, the only requirement being that each code element be prolonged for'a time suflicient to operate the relay which is selectively responsive to that code element. In actual practice, I have discovered that relays selectively responsive to the frequency of the currents utilized for code elements may be made to operate reliably upon code elements of the order of of a second duration. It is manifest that with a system operating upon this principle, the time required for each code is comparatively small and a large number of indications may therefore be handled over a single pair of line wires in a com paratively short time.

It should be pointed out that while I have, for purposes of illustration, shown and described one form of coding relay which may be utilized in practicing my invention, this particular form of relay is not essential but its function may be performed by any equivalent apparatus. In similar manner, I do not wish to limit my invention to the use of a stepping contactor of the type here described, as any other step-by-step device could be substituted for this mechanism.

It is also apparent that the actual control of -the devices at the remote station by the decoding relays, and the specific control of the indication three frequencies, the system can be utilized with a total of al remote stations and a corresponding number of panels. that by changing the number of code elements, or by changing the number of frequencies available for each element, a greater or smaller number of stations and panels may be controlled over a single pair of line wires.

Although I have herein shown and described only one form of remote controlling apparatus embodying my invention, it is understood that various changes and modifications may be made therein within the scope of the appended claims without departing from the spirit and scope of my invention.

Having thus described my invention, what I claim is:

1. In combination, a plurality of sources of currents of different characters, a plurality of devices each selectively responsive to a difi'erent one of such currents, means for repeatedly supplying all of said devices with current from selected ones of said sources in a predetermined sequence, receiving apparatus comprising a plurality of circuits one controlled by each said device, a plurality of magnets, including one in each of said circuits, and a contact controlled by said magnets, said contact being selectively responsive to the sequence in which said circuits are controlled.

2. In combination, a plurality of sources of currents of diflerent characters, a plurality of devices each selectively responsive to a different one of such currents, means for repeatedly supplying all of said devices with current from selected ones of said sources in a.predeter'mined sequence, receiving apparatus comprising a plu- It is manifest, however,

rality of magnets one controlled by each of said deviccs,.and a contact controlled by said magnets and selectively responsive to the sequence of operation of said magnets.

3. In combination with a movable device, a plurality of sources of periodic currents of different frequencies, a plurality of selecting relays each tuned to resonance at a different one of said frequencies, means controlled by said device for connecting said selecting relays with selected ones of said sources in a predetermined sequence which depends upon the position of saiddevice, a slow-acting relay arranged to be energized when any one of said selecting relays is energized, and indication means controlled jointly by said selecting relays and by said slow acting relay and selectively responsive to the sequence of operation of said selecting relays.

4. In combination with a line circuit, a plu rality of alternators delivering alternating currents of different frequencies, means for succcssively connecting selected ones of said alternators with said line circuit in a predetermined sequence, a plurality of frequency responsive line relays connected to said line circuit including one responsive to the frequency of each alternator,

a decoding relay having a plurality of magnets one for each said alternator and each arranged to be energized when the corresponding line relay is energized, and a contact controlled by the decoding relay and selectively responsive to the sequence of energization of said magnets.

5. In combination, a plurality of relays, means for energizing selected ones of said relays in a predetermined sequence, a device comprising a plurality of magnets, one for each such relay,

means for energizing each such magnet when the.

associated relay is energized, and a contact controlled by said magnets and selectively responsive to the sequence of energization of such magnets.

6. In combination, a plurality of relays, means for energizing selected ones of said relays in a selected sequence, a movable member biased to an initial position, means including drive magnets and effective upon each energization of any one of said relays in said sequence for moving said member away from such initial position, means for holding said member between such movements, and a contact controlled by said member.

'1. In combination with transmitting apparatus for delivering a code made up of a plurality of successive code elements of at least two different characters in a predetermined sequence, a plurality of relays one for each character of code element, means for energizing each said relay when a code element of corresponding character is transmitted by said apparatus, a movabe member biased to an initial position, means including drive magnets and efiective when said relays are energized in said predetermined sequence to progressively move said member stepby-step away from said initial position, said member being moved one step for each element of the code, and a contact controlled by said member and arranged to be clo ed at the conclusion of such code.

8. In combination, a plurality of stepping magnets, a holding magnet, a rotatable shaft having a plurality of non-magnetic disks, one for each magnet, a plurality of magnetic slugs placed in selected positions in said disks and under the control of the associated magnets, means for selectively energizing said magnets to attract the magnetic slugs one at a time lna predetermined order to cause step-by-step rotation of, said shaft, and a contact controlled by said shaft.

9. In combination, an electromagnet having spaced pole pieces, a movable lever having two magnetizable arms separated by an air gap and biased to one position but movable under the attraction of said electromagnet to a position in which said arms are adjacent said pole pieces respectively, a movable member having a magnetic slug located in said air gap and adapted to be held therein magnetically when said lever is moved in response to the energlzation of the electromagnet, and a contact controlled by said movable member.

10. In combination, a plurality of stepping magnets, a holding magnet, a. movable member biased to an initial position, means for successively energizing selected ones of said stepping magnets in a, predetermined sequence, means controlled by such stepping magnets and effective when the magnets are energized in said sequence for causing step-by-step movement of said member away from said initial position, means for energizing said holding magnet during the intervals between successive step-by-step movements of the member, means for preventing the return of said member to its initial position when said holding magnet is energized, and a contact controlled by said member.

11. In combination, a movable device, a source of code elements of different characters, a plurality of receiving devices one responsive to each character of code element, means for repeatedly supplying all of said receiving devices with selected ones of such code elements in different sequences depending upon the position of said movable device, and code responsive means controlled by said receiving devices and responsive selectively in accordance with the sequence of operation of such receiving devices.

12. In combination, a stepping contactor comprising a, series of contacts arranged to be closed in succession, a plurality of sources of currents of different characters, a line circuit, a plurality of delivery magnets one for each said source and each arranged when energized to connect the associated source with said line circuit, a plurality of manually operable levers, means set into operation upon a movement of any lever for operating said stepping contactor, and means operating when any contact of said series is closed to energize for a measured interval of time a selected one of such delivery magnets depending upon which lever was operated and upon the position such lever occupies.

13. In combination with a line circuit, a plurality of sources of periodic current of different frequencies, means for supplying said line circuit with successive code elements eachmade up of an impulse of current of a selected one of said frequencies, a plurality of relays all receiving energy from said line circuit and each arranged to close its contacts only when supplied with current of a different one of said frequencies, and a decoding device controlled jointly by said relays and selectively responsive to the sequence of operation of such relays.

.14. In combination with a line circuit connecting a plurality of remote stations and a control station, a plurality of devices at each station, a plurality of panels at the control station, means set into operation upon a change in the condition of any device at a remote station for supplying the line circuit with a code made up of code elements of equal lengths but different characters in a distinctive sequence, code responsive means at the control station for selecting a particular panel in accordance with the character of certain of said code elements, a plurality of indication devices for each panel, and means selectively responsive in accordance with the character of certain other code elements for selecting a particular indication device of said particular panel.

15. In combination with a line circuit connecting a control station and a plurality of remote stations, a plurality of panels at the control station including one for each station each provided with a plurality of manually controlled le-' vers, a plurality of governing devices at each remote station, means set into operation upon a change in the position of any lever at the control station for delivering to the line circuit a code made up of code elements of equal lengths but having different characteristics in adistinctive sequence, including certain elements identifying the panel containing the operated lever and other elements identifying the positions of the levers of said panel, a plurality of relays at each station one such relay at each station responding selectively to each character of code element, and means at each station for selectively controlling the devices at such station in accordance with the sequence of operation of the associated relays.

' 16. In combination with a line circuit, a plurality of sources of periodic currents of difierent frequencies, a plurality of delivery contacts one for each said source and each arranged when actuated to connect the associated source with said line circuit, a master relay having normal and reverse positions, a manually controlled lever, means controlled by a. reverse contact of said master relay for actuating selected ones of said delivery contacts for equal lengths of time in a predetermined sequence depending upon the position of said lever to deliver a complete code to the line circuit, means controlled by said lever for operating said master relay to its reverse position, and means efiective after the completion of said complete code to restore the master relay to its normal position.

17. In combination with an ofiice and a station connected by a pair of line wires, a source of periodic current, a relay, means for connecting said source and said relay in series across said line wires at said oflice, a normally open conducting path between said line wires at said station tuned to resonance at the frequency of said periodic current, means at said station for at times closing said path, and indication means at said oflice controlled by said relay.

18. In combination with an ofiice and a station connected by two line wires, a plurality of sources of periodic current of diiferent frequencies, a plurality of relays one for each such source, means for connecting each such source and the associated relay in series across said line wires at said oflice, a plurality of normally open contacts, a. plurality of conducting paths between said line wires at said station, each including one of said contacts and each tuned to resonance at a different one of said frequencies, means at said station for selectively operating said contacts, and indication means at said ofiice controlled by said relays.

19. In combination with an oflice and a station connected by two line wires, a plurality of sources of periodic current of different frequencies, a

au'meo plurality of relays one for each such source, means for connecting each such source and the associated relay in series across said line wires at said oflice, a plurality of normally open contacts, a plurality of conducting paths between said line wires at said station, each including one or said contacts and each tuned to resonance at a different one of said frequencies,

means at said station for operating selected ones of said contacts in a selected sequence, and indication means at said omce controlled by said relays and selectively responsive to the sequence of operation of said relays.

20. In combination, four decoding relays each having a contact arranged to be closed for a brief interval of time when the device is operated, two polarized relays, means for energizing one polarized relay in the normal direction when a first or a second decoding relay is operated, means for energizing said one polarized relay in the reverse direction when a third or a fourth decoding relay is operated, means for energizing said other polarized relay in the normal direction when said first or said third decoding relay is operated, means for energizing said other polarized relay in the reverse direction when said second or said fourth decoding relay is operated, two movable devices, means for operating one said device to one position or another according as said first polarized relay is energized in the normal or reverse position, means for operating the other said device to one position or another according as said second polarized relay is energized in the normal or reverse position, and means for selectively operating said decoding relays to control the positions of both said devices.

21. In combination with a line circuit, transmitting means arranged to deliver to said line circuit code elements of different characters in different sequences, a first group of relays controlled by the code elements delivered to said line circuit and selectively responsive to the character of each said code element, a second group of relays controlled by the relays of said first group and selectively responsive to the Sequence of operation thereof, and a third group of relays selectively controlled by the relays of the second group.

22. In combination with a line circuit, transmitting means arranged to deliver to said line circuit code elements of difierent characters in diflerent sequences, a first group of relays one for each character of code element, a receiver associated with said line circuit including means responsive to a code element of each character for effecting at any point in a sequence the selective operation of a definite one of such relays corresponding to the character of the received element, and a second group of relays controlled by and selectively responsive to the sequence of operation of the relays of said first group.

23. In combination with a line circuit, transmitting means arranged to deliver to said line circuit a series of code elements of different characters in different sequences, a first group of relays one for each character of code element, a receiver associated with said line circuit includ- Jng means responsive to a code element of each character for effecting at any point in a sequence the selective operation of a definite one of such relays in accordance with the character of the received element, a stepping device provided with a contact and means controlled by and selectively responsive to the sequence of operation of mit ting means arranged to deliver to said line circuit a seriesof code elements each having a selected one of at least three diiferent characters, a receiver controlled by the code elements delivered to said line circuit and selectively responsive to the character of each code element, stepping means controlled by said receiver, and means governing the operation of said stepping means in accordance with the sequence of the different characters or said code elements.

25. In combination, a line circuit, means for transmitting to said line circuit a code made up of a series of code elements each having a selected one of at least three different characters, receiving means controlled by the code elements delivered to said line circuit and selectively responsive to the character of each element, a three-position movable device, stepping means controlled by said receiving means adapted to operate said device to any one of its three positions in accordance with the character of one element of the code, and means governing the operation of said stepping means in accordance with the sequence in which code elements of different characters occur in said code.

26. In combination, a line circuit, means for transmitting to said line circuit a code made up of a series of code elements each having a selected character, receiving means controlled over said line circuit and adapted to register the character of each of the successive elements of said code, stepping means controlled by said receiving means, means requiring a code having code elements arranged in a definite sequence for operating said stepping means. progressively, and means effective upon the progressive operation of said stepping means by a complete code to register said code.

27. Receiving means for codes made up of series of code elements each having a selected character comprising a group of devices each supplied with every element of said codes but each selectively responsive to'elements o! a different character, and stepping means controlled by said devices and selectively responsive to the particular device which responds during each code element and arranged to be operated progressively through a number of steps corresponding to the number of elements it and only if said devices respond in accordance with a single predetermined sequence.

28. Receiving means for codes made up of series of code elements each consisting of an impulse of current of a selected one of at least three different frequencies, comprising a group oi frequency selective relays each supplied with every element of said codes, and registering means controlled by said relays and selectively responsive to the particular relay in said group which responds during each code element only if said relays are operated in a predetermined sequence.

29. A centralized trafiic controlling system for railroads comprising an oflice and a station, two line circuits connecting said oflice and station, a plurality of sources of currents of difierent characters at said ofilce, means for connecting said sources with one said line circuit in a predetermined sequence to deliver a code to said station, receiving means at said station selectively responsive to saidcode, railway traiilc governing means at said station selectively controlled by said receiving means, indication means at the oillce responsive to the flow of current from said sources in the other saidline circuit, and means responsive to traflic conditions at said station for controlling the current in said other circuit.

30. A centralized trafiic controlling system' for railroads comprising an oflice and a station, two,

line circuits connecting said office and station, a plurality of sources of currents of different characters at said oflice, means for connecting said sources with one said line circuit in a predetermined sequence to deliver a code to said station, receiving means at said station selectively responsive to said code, railway traflic governing means at said station selectively controlled by said receiving means, indication means at the oiiice responsive to the flow of current in the other said line circuit, means for constantly con-.

necting at least one of said sources with said other.

line circuit, and means responsiveto traflic conditions at said station for controlling the current in such other line circuit.

31. "A centralized trafilc controlling system for railroads comprising an oflice and a plurality of stations, two line circuits extending from said .ofllce to all of said stations, a plurality of sources of currents of different characters at said oiiice, means for connecting said sources with one said circuit in different sequences to transmit distinctive codes to said stations, receiving means at each station selectively responsive to said codes,

railway traflic governing means at each station controlled by the associated receiving means, indication means at the ofllce responsive to current flowing in the other said line circuit, means for constantly connecting at least one of said sources with said other circuit, and means at each station controlled by tramc conditions at. such station for controlling the current in said other line circuit.

'32. A centralized tramc controlling system for railroads comprising an ofllce and a plurality of stations connected by a line circuit, a plurality of levers at said oflice one for each said station and each having a plurality of control positions, a plurality of current sources at said oiiice, means responsive to a change in the position of any lever for connecting said sources selectively with said line circuit in a sequence which depends upon the particular lever which was operated and for subsequently connecting a particular one of said sources with the line circuit depending upon the position then occupied by such lever to produce an operating impulse, receiving means at each station selectively responsive to said sequence to select the particular station corresponding to the operated lever, a traffic governing device at each station, and means at each station effective when the associated receiving means is actuated to control the corresponding traflic governing device selectively in accordance with the particular source connected with said line circuit during said operating impulse. I

33. In combination, a-railway system, a central oflice from which train movements over said system may be directed, a plurality of way stations, a trafiic controlling device at each way station, a line circuit connecting said central office and said way stations, and means for distinctive- 1y operating said traflic controlling devices over 34. In combination, a railway system, a .central ofllce from which train movements over said system may be directed, a plurality of way sta- Y tions, a track circuit at each way station, a line tral ofllce from which train movements over said system may be directed, a plurality of way stations, a track circuit at each way station, a line circuit connecting said central omce and said way stations, and means for distinctively indicating at said central ofllce the occupancies of the various track circuits including code creating and code responsive devices for creating and deciphering codes each code of which comprises a plurality of distinctive frequency impulses given in a distinctive order.

36. A centralized tramc controlling system for railroads comprising an ofiice and a station, two line circuits connecting said oiiice and station, a plurality of sources of current at said ofllce, means at said oflice for supplying to one said line circuit from said sources a series of code elements each of distinctive character in a predetermined sequence, receiving means at said station selectively responsive to said series, railway trafiic governing means at said station selectively controlled by said receiving means, indication means at the office responsive to code signals in the other said line circuit, means for constantly connecting said sources with said other line circuit, and means responsive to trafllc conditions at said station for controlling the current in such other line circuit to produce code signals therein.

37. A'centralized traflic controlling system for railroads comprising an ofiice and a plurality of stations, two line circuits extending from said omce to all of said stations, a plurality of sources 01' current at said otiice, means at said oflice for supplying to one said line circuit from said sources a series of distinctive code elements, receiving means at each station selectively responsive to said series, railway trafllc governing means at each station controlled by the associated receiving means, indication means at the office responsive to code signals in the other said line circuit, means for constantly connecting said sources with said other circuit, and means at each station controlled by trafllc conditions at such station for controlling the current in said other line circuit to produce code signals therein.

38. A centralized traflic controlling system for railroads comprising an oflice and a station, two line circuits connecting said oflice and station, a plurality of Sources of current at said ofllce, means at said ofllce for supplying from said sources to one said line circuit a series of code elements arranged in predetermined sequence, receiving means at said station selectively responsive to said series, railway traflic governing means at said station selectively controlled by said receiving means, indication means at the oflice, contact mechanism controlled by said traflic governing means; and means including the other said line circuit, said contact mechanism, and said sources for controlling said indication means.

39. In a centralized trafflc controlling system for railroads, an oflice and a plurality of stations connected by a line circuit, a plurality of sources of current at said ofllc'e, a plurality of control panels at saidwfllce each providedwith a movable lever, means controlled from any panel for transmitting a codeproduced by connecting at least one of said sources with said line circuit to create a sequence of code elements each of a particular character of which sequence one part is controlled in accordance with the corresponding panel and another part is controlled by the position of the lever associated with said panel, a traflic governing device at each said station, receiving means at each station selectively responsive to said one part of said sequence, means at each station efiective when the associated receiving means is selected to control the traflic governing device at such station in accordance with said other part of the sequence, and other means including at least one of said sources for indicating the position of each said traflic governing device on the corresponding ofiice panel.

40. In combination with a plurality of groups of movable devices, code tran'smittingmeans for producing a series of code elements each comprising an impulse of current of determinable character, means for initiating operation of said code transmitting means from any of said groups, means for determining the character of current comprising certain elements of each said code in accordance with the group from which the code was initiated, and means responsive to the condition of the devices in such group for determining the character of current comprising the remaining elements of said code, and receiving means responsive to the character of the current comprising each of the elements of said code.

41. Code transmitting apparatus comprising a plurality of independently operable starting devices, a series of code sending relays one for each said starting device, means for operating the first code sending relay in said series which has its starting device operated, means efiective when a code sending relay is operated to transmit a series of code elements arranged in a definite sequence and each comprising an impulse of a selected one of a plurality of characters of current, and means eflfective upon the completion of said series of code elements to restore the operated code sending relay to its original condition and to operate the next code sending relay in said series which has its corresponding starting device operated.

42. In a remote control system of the code type, transmitting apparatus for delivering codes made up of selecting elements and function elements each comprising an impulse of a selected one of a plurality of characters of current, a plurality of groups of movable devices, a code sending relay for each said group, means for selectively energlzing'any one of said code sending relays and for preventing the energization of any other code sending relay while the selected relay is energized,

means controlled by the energized relay for initiating the operation of said transmitting apparatus and for determining the character of each selecting element of the resulting code, means controlled by the energized relay and by the devices of the associated group for determining the characters of the function elements of said resulting code, and receiving means selectively responsive to each element of each code delivered by said transmitting apparatus.

43. A remote control system comprising an omce and a plurality of stations connected by a line wire, a plurality of sources of periodic currents of different frequencies at said ofiice, a distributor comprising a series of contacts and means for closing said contacts in a predetermined order, means including the contacts of said distributor for connecting said sources with said line wire in different sequences to produce different code signals, receiving means at each station selectively responsive to currents of said different frequencies, and a selector at each station controlled by the receiving means at that station and individually responsive to a particular one of said code signals.

44. A remote control system comprising an oflice and a plurality of stations connected by a line wire, a plurality of sources of periodic currents of different frequencies at said office, a distributor comprising a series of contacts and means for closing said contacts in a predetermined order, means including the contacts of said distributor for connecting said sources with said line wire selectively to produce different code signals, each comprising a sequence of frequencies individual to a particular station, receiving means at each station each including a frequency responsive relay for each frequency of the code signal individual to such station, and a selector at each station controlled by the associated receiving means and selectively responsive to the code signal individual to such station.

45. A remote control system comprising an oifice and a plurality of stations connected by a line wire, a plurality of sources of periodic current of different frequencies at said ofiice, a

distributor at the office comprising a series of contacts closed in a predetermined order, means controlled by the contacts of said distributor for connecting said sources with said line wire selectively to produce different signals one for each said station, a selector at each said station individually responsive to the signal for that station, a device at each station and a control lever at the oifice for each said device, and means responsive to the movement of one of said levers for actuating the station device corresponding to the operated lever in accordance with the position then occupied by such lever when the distributor has been operated to a predetermined position provided only the selector at the station where the device is located has responded to the signal for such station.

46. In a remote control system comprising an office and a plurality of stations connected by a line wire, a movable device at each station, a control lever at the office for each device, means set into operation by a change in the position of any lever for delivering to the line wire a code comprising a sequence of periodic currents of selected frequencies, a frequency responsive relay for each frequency of each such code at each station, and means at each station controlled by the associated frequency responsive relays for selectively controlling the device at such station when the associated relays are actuated in a sequence which is in accordance with a particular one of said codes.

47. A centralized traflic controlling system for railroads comprising an oflice and a plurality of stations connected by a linewire, a railway traffic governing device at each station, a control lever at the office for each device, means set into operation by a change in the position of any lever for delivering to the line wire a code comprising periodic currents of selected frequencies, a frequency responsive relay for each frequency of each such code at each station, receiving means at each station selected only when the associated relays are actuated in accordance with a particular one of said codes, and means at eachstation controlled by the associated receiving means when selected to control the device at such station in accordance with the position then occupied by the corresponding lever.

48. In a remote control system including a line circuit, code transmitting apparatus comprising a movablelever, a master relay normally occupying one position, means controlled by said lever for operating said master relay to a different position, a plurality of sources of periodic currents of different frequencies, and a distributor effective when said relay occupies said different position to connect said sources with said line wire selectively to produce a distinctive signal the character of which depends in part upon the position then occupied by said lever.

,49. In a remote control system including a line circuit, code transmitting apparatus comprising a plurality of movable levers, a master relay normally occupying one position, means controlled by any said lever for operating said master relay to a different position, a plurality of sources of periodic currents of different frequencies, and a distributor effective when said relay occupies said different position to connect said sources with said line wire selectively to produce a distinctive signal the character of which depends in part upon the particular lever which caused the operation of said master relay and in part upon the position of such particular lever.

50. A remote control system comprising an office and a plurality of stations connected by a line wire, a plurality of sources of periodic current of different frequencies at the oflice, means at the oflice for connecting said sources to the line wire selectively to produce different signals one for each station, a selector at each station selectively responsive to an individual one of said signals, a manually controlled communication channel rendered available from the office to a particular station when the selector at such station is actuated, and means for transmitting a message over said channel to perform a selected operation at such station.

51. A centralized traffic controlling system for railroads comprising an office and a plurality of stations connected by a plurality of frequency responsive communication channels all including the same line wire, a distributor operable through a cycle and effective during each cycle to close said channels selectively to produce different signals in said line wire, selector means for each station selectively responsive to said signals located at said oflice, a track section at each station, means for operating said'distributor, means effective when any said section becomes occupied to close a particular one of said channels during the operation of said distributor, and frequency responsive means at the office responsive to the closing of said particular channel provided only the selector associated with the corresponding station has been operated for indicating the occupancy of the track circuit at such station.

52. A centralized traffic controlling system for railroads comprising an office and a plurality of stations connected by a plurality of frequency selective communication channels all including the same line wire, a plurality of sources of periodic currents of different frequencies at the oflice, means at the office for selectively delivering currents from said sources to said channels in different sequences to produce different code signals, a plurality of relays at each station, one

in each said channel, and a selector at each station controlled by the relays at such station and operating only when said relays are actuated in a sequence corresponding to a particular one of said code signals individual to such station.

53. In combination, a railway system, a central office from which train movements over said system may be directed, a plurality of way stations, a traffic controlling device at each way station, a line circuit connecting said central oflice and said way stations, and means for distinctively operating said traffic controlling devices over said circuit including code creating mechanism at said central oflice and code responsive mechanism at said way stations for respectively creating and deciphering codes of which each code comprises a plurality of distinctive frequency impulses.

54. In power operated railway switch and signal mechanism, a control panel comprising a panel board with the track layoi'it indicated on the face thereof, a plurality of manually movable control members corresponding to the several track switches to be controlled, each control member comprising a manually oscillatable switching device having a route indicating member located on the face of the panel to cooperate with the track layout indicated thereon, and an electric switch mechanism carried by the panel and comprising a contact attached to said indicating member and movable therewith.

55. In power operated railway switch mechanism, a control panel comprising a panel board with the track layout indicated'on the face thereof, a plurality of manually movable control members corresponding to the several track switches to be controlled, each control member comprising a manually oscillatable switching device having a route indicating member movable on the face of the panel to cooperate with the track layout indicated thereon, and an electric switch mechanism mounted on the panel and comprising a contact member attached to said indicating member.

56. The combination, with a railway track switch and power mechanism for operating said switch, of a track model comprising a panel having a graphic representation of the main track and the siding track connected by said track switch, a miniature track switch located on the front of said panel and movable in a plane parallel to the panel and by its position with respect to said graphic representation representing the position to be assumed by the switch, a handle attached directly to said miniature track switch and adapted to be grasped by the operator for moving said miniature switch, a movable contact driven by said handle, a fixed contact cooperating with said movable contact, and means controlled by said movable contact and said fixed contact for governing said power mechanism.

57. In combination with a railway trafiic governing device having an operating circuit, a rotatable member, a contact carried by said member, a fixed contact cooperating with the contact on said member .to control the operating circuit for said device; means for imparting a step by step rotation to said member comprising a series of elements positioned on said member, a plurality of stepping yokes one for each said element, and electromagnetically actuated means for independently operating each stepping yoke; means for returning the member directly to normal position from the position reached by the step by step rotation, and electrically controlled means for retaining said member in certain predetermined positions.

58. In combination with a plurality of railway traflic governing devices, a control panel comprising a panel board with the track layout indi- ,the position to be assumed by the corresponding device, a single rotatable element, electromagnetic means under the control of said members for imparting step by step rotation to said element, and contacts controlled by said element for selectively operating said trafiic governing devices into positions of correspondence with the associated indicating members.

59. A centralizedtraffic control system for railroads comprising an ofiice and a station, a railway switch at the station, signals for governing trafllc in opposite directions over said switch, a switch lever and a signal lever at said office each capable of assuming two positions, means at the oflice for transmitting to the station distinctive codes having characters determined by the positions of both said levers, four relays at the station each selectively responsive to an individual one of said codes and corresponding respectively to four possible combinations of positions of said levers, control means actuated to move said switch to normal and clear a signal for traffic in one direction when one said relay is operated, to move said switch to normal and clear a signal for traflic in the other direction when a second said relay is operated, to move said switch to reverse and clear a signal for traiiic in said one direction when a third said relay is operated, and to move the switch to reverse and clear a signal for traflic in said other direction when the fourth said relay is operated, and means for retaining said control means in its actuated condition after the termination of a code.

60. A centralized trafiic control system for railroads comprising an office and a station, a railway switch at the station, signals for governing traflic in opposite directions over said switch, a switch lever at the office capable of assuming two positions, a signal lever at the oifice capable of assuming three positions, means at the ofiice for transmitting to said station one of four distinctive codes each determined by both said levers in their extreme positions and a fifth code when the signal lever occupies its middle position, five relays at the station each selectively responsive to one of said codes, control means actuated to move said switch to normal and clear a signal for trafilc in one direction when one said relay is operated, to move said switch to normal and clear a signal for traffic in the other direction when a second said relay is operated, to move said switch to reverse and clear a signal for 'traiiic in said one direction when a third said relay is operated, and to move the switch to reverse and clear a signal for traiiic in said other direction when the fourth said relay is operated, and to put all said signals at stop when the fifth said relay is operated, and means for retaining said control means in its actuated condition after the termination of a code.

61. In a dispatching system, a dispatchers office, a way station, a track switch and signals at said station controllable to set up four possible routes for train movements, four control relays at the station each operable to govern both the 

